Identification of Potential Carbonic Anhydrase Inhibitors for Glaucoma Treatment Through an In-Silico Approach

Glaucoma is a neurodegenerative disease and second leading cause of blindness in western world. The disease is characterized by an elevated intraocular pressure. Carbonic anhydrase plays a major role by forming aqueous humor and its inhibition can reduce intraocular pressure by partially suppressing the secretion of aqueous humor. Thus in this study, we proposed to identify the potential novel compounds targeting the carbonic anhydrase. The diversity set-II molecules library consisting of 1880 compounds from National Cancer Institute were virtually screened (molecular docking) against human carbonic anhydrase protein. For the obtained best compounds, the nature of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), which determine nucleophilic and electrophilic activity, were calculated by using density functional theory (DFT). The in silico screening suggested 5 best compounds that are effective in comparison to the dorzolamide, a widely used carbonic anhydrase inhibitor for glaucoma treatment. Of the five compounds, 4-nitro-7-[(1-oxidopyridin-1-ium-2-yl) thio] benzofurazan (ZINC01757986) exhibited the better binding affinity (- 9.2 cal/mol) in comparison to dorzolamide (- 7.2 kcal/mol). The DFT studies on novel identified compound, ZINC01757986 exhibited less HOMO-LUMO energy gap, low hardness and more softness (0.2305 eV, 0.1152 eV and 8.6805 eV) when compared to dorzalamide (0.9536 eV, 0.4768 eV and 2.0973 eV). These studies emphasize that ZINC01757986 can be used as potential carbonic anhydrase inhibitor and lead compounds for the development of an effective anti-glaucoma drug. The results emphasize that these compounds could be potential lead molecules for further structure-based discovery of antiglaucoma drugs.